I tried to get the dealer to add the upfitter/taxi wiring to my recent 2015 LWB wagon purchase. After initially being told it was possible by both the sales and service managers along with the shop foreman, eventually I had to talk to the "wiring specialist" for the shop who told me why it could not be done. Not only does Ford not include the wiring for the extra circuits, they don't even make it possible to use the fuse block to add the circuits. Only the supply side of the fuse has the connector. If not factory wired for an option, the load side of the fuse doesn't have anything installed. You can see there is no metal connection under the plastic cover for all the blank fuse slots. And they said even for repairs they can't order just the connectors from Ford, they have to replace the entire fuse panel.
I had the dealer run some wires for me but they had splices in the middle and different colored wires on each end. I didn't like their workmanship so I redid it myself last week. To do it how I wanted cost a couple hundred dollars in parts, but that was mostly because the small pieces had a minimum order of 100. I've got enough parts on hand to repeat my install on 6 vehicles plus build connectors for another 15-20. I'll be trying to do a writeup on my modification in the next couple days.
But as for the wiring diagrams, here's pix for the 2015 Transit Connect Taxi/Customer Access section.
The last one is the money shot on the final hookup I did at the cargo area fuse block.